This invention relates to a method and means of processing any single-emulsion photographic film or plate in a manner so that it has certain characteristics of a double emulsion film or plate thereby rendering it capable of recording phase and amplitude information at separate depths of the emulsion.
The central problem in computer generated optics and holography is obtaining a high resolution transparency of superior optical quality which can control both the amplitude and the phase of transmitted light at each point in accordance with a computed complex function. In attempting to solve this problem, a number of different approaches have been taken including making a sandwith of two independent transmitting layers. However, the solutions including the making of the sandwich structure are not simple to either make or use and often produce deleterious and unwanted side effects. In a scientific journal, "Applied Optics", July, 1973, Volume 12 No. 7, page 1386, there is described in an article entitled "Multi-Emulsion On-Axis Computer Generated Hologram" a solution which utilizes color film. However, color film is a multi-emulsion film, the characteristics of which are optimized by the manufacturer for purposes of color photography, not for computer generated optics.